Liquid chromatography-mass spectrometric determination of losartan and its active metabolite on dried blood spots.

A simple and rapid quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for simultaneous determination of losartan and its active metabolite, losartan carboxylic acid on rat dried blood spots was developed and validated as per regulatory guidelines. Losartan and its metabolite were extracted from dried blood spots using 50% aqueous methanol and separated on Waters XTerra(®) RP18 (250 mm × 4.6 mm, 5 µm) column using mobile phase composed of 40% acetonitrile and 60% aqueous ammonium acetate (10mM). The eluents were monitored using ESI tandem mass spectrometric detection with negative polarity in MRM mode using ion transitions m/z 421.2→179.0, m/z 435.3→157.0 and m/z 427.3→193.0 for losartan, losartan carboxylic acid and Irbesartan (internal standard), respectively. The method was validated over the linear range of 1-200 ng/mL and 5-1000 ng/mL with lower limits of quantification of 1.0 ng/mL and 5.0 ng/mL for losartan and losartan carboxylic acid, respectively. Inter and intra-day precision and accuracy (Bias) were below 5.96% and between -2.8 and 1.5%, respectively. The mean recoveries of the analytes from dried blood spots were between 89% and 97%. No significant carry over and matrix effects were observed. The stability of stock solution, whole blood, dried blood spot and processed samples were tested under different conditions and the results were found to be well within the acceptable limits. Additional validation parameters such as influence of hematocrit and spot volume were also evaluated and found to be well within the acceptable limits.

The new method developed for evaluation of anthelmintic activity by housefly worms and compared with conventional earthworm method.

Evaluation of anthelmintic activity of any drug when carried out in laboratory conditions by using the isolated worms from nature cannot be adaptable with artificial laboratory conditions. Therefore, the present study aims at developing a new adaptable method for evaluation of anthelmintic activity. The present anthelmintic activity study reveals a new methodology with housefly worms cultured in laboratory conditions that resemble parasitic pinworms found in human being. We studied the anthelmintic activities of various drugs on housefly worms and earthworms. The results showed that the housefly worms had taken more time for paralysis and death. Even after paralysis the time taken for death is more in housefly worms in spite of smaller size and lesser weight of the worms compared to earthworms. The study concluded that the earthworms have not adapted to the artificial laboratory conditions leading to erratic results. Therefore, culturing of housefly worms was carried out to evaluate the anthelmintic activity and found an easy, prominent, eco-friendly, and reproducible method in all aspects such as equal age, size, and weight of worms used for the experiment.